Question

Byron draws a ray diagram to show how an image is produced by a lens.

A flower is the object in front of a biconcave lens and is farther than 2 F from the lens. A ray parallel to the principal axis is labeled X and bent away from F. A second light ray toward F on the image side of the lens is bent parallel to the principal axis is labeled Y. The image is closer to the lens than F on the object side of the lens, is the same size as the object and erect.
Which describes Byron’s error?

The image should be smaller than the object.
The incident ray labeled X should continue moving in the same direction.
The image should be inverted instead of upright.
The incident ray labeled Y should continue moving in the same direction.

Answer 1

The image should be smaller than the object.

A biconcave (diverging) lens always produces a virtual, upright, reduced image for a real object. The ray directions Byron drew are correct, but the image size being the same as the object is wrong.